Comprehensive and Detailed Explanation From Exact Extract:

The described activity—visiting a website and downloading publicly accessible content—is a classic example of passive reconnaissance. Passive reconnaissance involves gathering information about a target without interacting with its internal systems or generating traffic that could be detected by security monitoring tools.

According to SY0-701, passive recon uses open-source intelligence (OSINT), such as:

Public websites

DNS records

News articles

Metadata

Public document repositories

The key distinction is that passive reconnaissance does not probe the system for vulnerabilities, nor does it send active scanning traffic.

Vulnerability scanning (B) requires active probing. Unknown environment testing (A) applies to black-box testing but still may involve active scanning. Due diligence (C) refers to risk assessment or compliance reviews, not technical reconnaissance.

Therefore, downloading the website’s content is a non-intrusive information-gathering technique, perfectly matching passive reconnaissance as defined in the exam materials under Threats, Vulnerabilities, Attack Vectors, and Pen Testing Phases.